Stress Engineering in Developing Mixed Conducting Si-Ge Solutions for Lithium Ion Batteries

Wednesday, October 14, 2015: 10:00
Remington B (Hyatt Regency)
K. Mishra, M. Geppert (University of South Carolina), and X. D. Zhou (University of South Carolina)
Despite having the highest theoretical specific capacity (3579 mAh/g), silicon has been known to undergo massive anisotropic volume expansion (~280%), and consequently, causing the fracture of the particles and loss of the specific capacity upon further cycling. Germanium has been reported to undergo isotropic expansion and observed in the in-situ studies to sustain lithiation induced fracture up to the particle size of ~680 nm. In this work, solid solution of Si and Ge of various compositions were synthesized. The formation of a single phase solid solution was confirmed by the X-ray diffraction and the electrode morphology were studied using Scanning electron microscopy.  The solid solution of equimolar Si and Ge (Si0.5Ge0.5) displayed excellent electrochemical performance both in the cyclic stability as well as the total specific capacity.